Question: Simplify the following expression: $k = \dfrac{n^2 - 4n - 12}{n - 6} $
First factor the polynomial in the numerator. $ n^2 - 4n - 12 = (n - 6)(n + 2) $ So we can rewrite the expression as: $k = \dfrac{(n - 6)(n + 2)}{n - 6} $ We can divide the numerator and denominator by $(n - 6)$ on condition that $n \neq 6$ Therefore $k = n + 2; n \neq 6$